though it also shows a fair bunch of syntax errors (I guess originating from differences between FreeBSD's and Linux's bashes?)

So.

What should I do next?

I see several ways:

1. try to hack this script to let it accept FreeBSD and see what happens (looks like a random attempt...).

2. find a way to correctly start this rpm-installed software (Should I chroot before I run it? Is there at all a way to let it think it's actually running under Linux, something similar to a jail environment?)

The one from github I tried some months ago, it didn't work anymore (support of electron has been dropped).
It ended up this way: https://www.bountysource.com/issues/290 ... o-electron
I give it a try again, right now, and still does not work, though I see the issue seems different than before.

Well this drives crazy. It stops at this: npm install chromedriver -g with a permission error (a directory not being writable). As it does not exist, I created it and gave permission (full write access, just to see), then I get a too many symbolic links error, no idea what to do about it.

From an issue for another project in github, it looks like the fix is to not install system-wide, what looks required by the steps for TrueOS... and it requires a nvm command that I cannot find in the repos. So, I think I give up with this way